Botulinum toxin injections for strabismus (squint) during pregnancy and breastfeeding- FAQ’s

Has botulinum toxin previously been given to pregnant women?

Yes. There are published reports of botulinum toxin being given to pregnant women to treat a range of conditions, including squint.

What dose of toxin was used?

The dose of botulinum toxin given for various symptoms of squint ranged from 1.25 to 400 units. The dose we use to treat squints at Moorfields is 2.5 units in both pregnant and non-pregnant women.

Were there any problems reported in the pregnancy of women who had toxin injections?

Published medical studies to date have shown no additional risk in pregnancy in those who received botulinum toxin compared to that of the general population. This included information over a 24 year period which involved 232 pregnancies.

Has botulinum toxin been given to pregnant and/or breastfeeding women at Moorfields?

Yes, and to date, we have had no reported complications.

Is it medically safe to have botulinum toxin while breastfeeding?

There is no published information about the medical use of botulinum toxin in breastfeeding. There is one published case report of a woman with botulism (a very rare but life- threatening condition caused by toxins produced by bacteria) who safely breastfed herinfant and no botulinum toxin was found in her milk. However, we know botulinum toxin has been found in the breast milk of animals with botulism.

Have there been any harmful effects of botulinum toxin reported during pregnancy in animals?

Yes. In experimental studies using rabbits, daily injections led to maternal toxicity, miscarriage and foetal abnormalities.

What is Moorfields’ advice on this?

Medically, we would suggest that no medication, unless it is absolutely necessary, should be given during pregnancy or breast feeding. Although the current limited evidence available would suggest there have been no harmful effects in humans, safety cannot be completely guaranteed; there is the potential risk of miscarriage or abnormalities in the baby, or botulism if breastfeeding.

What should I do if I wish to proceed with the botulinum toxin injection?

You will need to inform your doctor and sign a new consent form to confirm you have read this information, are aware of and understand the potential risks and wish to proceed with the injection. If you are breastfeeding, we strongly advise that you express your milk to use for 24-48 hours following the injection.

Author: Gill Adams, strabismus service director 

Review date: March 2020